Degradation of norfloxacin with peroxymonosulfate activated by nanoconfinement Co₃O₄@CNT nanocomposite

In this work, the tube-filled nanocomposites Co₃O₄@CNTs were successfully prepared and applied for the first time in the permonosulfate (PMS) system to degrade norfloxacin (NX). Characterization results showed that Co₃O₄ nanoparticles served as independent templates and were randomly distributed onto the surface of the internal cavity of CNTs. After five cycles, the removal rate of NX decreased by only 4.5%, indicating its high catalytic activity and stability. This study also proposed a potential mechanism based on Co₃O₄@CNT/PMS system catalysis in which ¹O₂ was the main cause of NX degradation. DFT calculation results confirmed that the electronic activity of Co₃O₄ filled CNTs increased, and that the Co₃O₄ nanoparticles filled in the tube were the main catalytic sites of Co₃O₄@CNTs for NX degradation. This work provided the first insight into the effects of metal nanoparticles in the confined structure of CNTs on PMS activation.